Electrical Shock

[hsdancer]

Help. I've got a problem with my pool that is baffling me. When I reach out from the pool and touch the pavers (wet) I get a mild shock. I have measured the voltage from the pool water to the sand in the cracks of the pavers and get 4.5vac. I checked the bond wire at the pump and it is connected properly to the lug (The bond wire, #8 solid coper, goes all the way around the pool and attaches to the coping every two feet). In my attempt to trace the problem to its source, I turned off the main power at the house (which feeds the house as well as the pool house and pump), and I still get the 4.5vac. I have no other source of power in the house, so I assumed that the problem was coming from the SMECO (our power company). They came out and took some measurements and said that the problem was not on their end.

When I disconnect the bond wire from the pump lug, the shock goes away, but there is a potential difference of 4.5vac between the pump case and the bond wire. I ran an additional #8 ground wire between the pump lug and the electrical ground box, and the shock is still present.

Basically, I think that I have a 4.5vac potential on my entire house ground, but have no idea of what to do.

Is it possible that our saltwater pool (with lots of iron in the soil) could be a generator?

Any ideas?

Thanks.
Cliff

[duraleigh]

Hi, Cliff,

I am ignorant about bonding but JohnT gave me some good advice. He is particulary knowledgeable and may be able to help. (There are others on the forum who have a handle on it as well but I can't think of their usernames right now)

I'd PM him so he doesn't miss this post. As you obviously realize, it's a problem that needs resolution.

[huskyrider]

The few times I've seen situations (except in ours you felt a very mild shock when touching the water) like yours the problem ended up being the neutral. I don't know what the power company did to fix or where they found the problem with the neutral wire.
Good luck!!!

See Ya,
Kelly

[JohnT]

Stray voltage is pretty common, but not always easily explained. The most common cause is less than ideal grounding practices on transmission lines. Other possible sources are non-code wiring by neighbors, malfunctioning electric motors, and defective neutral wires in the area.
Bonding should keep you from feeling the stray voltage at the pool. The effect you are seeing is probably a result of your deck being unbonded. Normally, the deck of an inground pool is bonded via the rebar in the concrete. In your case, this is not possible.
What I think might be causing this the fact that the pool deck is grounded by contact with the earth at the pool, but the pool equipment is grounded via the pump bond lug at the house's service entrance. Even without a stray voltage situation, the voltage of the ground varies quite a bit over even short distances.
Before doing anything, I would suggest you verify that your electrical service is properly grounded at the service entrance, and that the neutral connections are tight in your box. Then contact your power company and tell them you are having stray voltage issues, and ask if they can come out and verify the connections in their equipment. They may not be much help, but if you happen to live in an area that experiences this regularly, they might be a big help.
With all of that said and done, if it were my pool, I would try adding an 8 ft copper ground rod near the pump, and connecting it to the bond lug on the pump in addition to the existing bond wire. Although this is not required by code, it isn't disallowed either. My hunch is this will solve your problem of being shocked.
I've never thought about the issue of using pavers for a deck as it relates to bonding before. There is new version of the NEC in the works, and it appears it will require a copper mesh under the entire pool area as part of the bonding system. I would suspect that to be safe, a paver deck should have this mesh under it as well, and that technically it isn't to code without it now, since the wet pavers are condcutive.

[MarkC]

A coworker of mine also had this issue and in his case it was found to be caused by some problem with the cable TV wiring on his site.

[cleancloths]

I would suggest you go back to square one. Turn off the main breaker to the house and see if you still measure a voltage - that will rule out your electrical system. If you still do, then turn the main on and all the other breakers off, is it there? If not, turn on one breaker at a time and take measurements. It might be an open neutral on one circuit or a ground/neutral reversal somewhere.

[South_Texas_Sun]

Hi hsdancer,

You didn't give enough info about your pool to "diagnose" the electrical fault, but you did mention that disconnecting your "bond" wire (I assume that's another name for the ground wire/lug) stopped the voltage flow.

If I were you. I would get an 8' copper ground stake from the electrical dept. at Home Depot/Lowes (about $13) and pound it into the ground near your pool and equipment pad, then connect the chassis ground lugs on your equipment to the copper EARTH GROUNDED stake.

Many times, the "service ground" wire from the power company has a potential voltage above earth ground and a potential can develop on anything connected to the power company ground but grounded WELL to earth ground.

I can't THINK of a better way to ground YOURSELF than being immersed in SALT WATER and touching a source voltage! (lol.....sounds dangerous, doesn't it?

Also, I would worry about being able to physically "feel" 4.5VAC. Normally it takes a larger voltage than that to be able to feel a shock. (for example, the low 12vdc voltage but nearly unlimited instantaneous current flow available from an ordinary car battery.)

What I'm saying is....it may be a MUCH larger voltage that you're just unable to measure for some reason. (autoranging meter? wet spot not salty, etc.)

So I would also check that you have the electrical equipment connected correctly with matching "hot" and "return" lines connected the same way on all equipment.

You may have heard of rock stars who have been electrocuted by touching the microphone in wet weather (which is usually caused by plugging the sound reinforcement into ungrounded or reverse wired outlets) and you MAY be in a similar situation here, so I would check it out before you have a real accident.

Any indication of stray voltage like this is potentially EXTREMELY HAZARDOUS and is an accident just waiting to happen to someone who unwittingly makes a "better connection" and sits or somehow touches the wrong spot on the pool. Fortunately, it's a simple fix even if we don't completely understand why the problem exists.

Hope that helps

STS

[johnm92627]

I would suggest you go back to square one. Turn off the main breaker to the house and see if you still measure a voltage - that will rule out your electrical system. If you still do, then turn the main on and all the other breakers off, is it there? If not, turn on one breaker at a time and take measurements. It might be an open neutral on one circuit or a ground/neutral reversal somewhere.

I am an electrical contractor and I would have to agree this is the best way to start. If it doesn't locate your problem (but it should) then drive the ground rod.

[JohnT]

Sure hope it isn't a sign of problems to come!
Good luck!

It is a sign of problems. Your pool deck isn't bonded, and if it were to come in contact with a higher voltage source, you could be electrocuted when you touch the deck. Your pool company screwed up. Your electric company fixed a symptom, not the root problem.

[South_Texas_Sun]

I'm an EE by training and home/pool wiring is not rocket science. I joke with my brother in law about being a "4 wire technician" because that's pretty much what he does as an electrician.

But you absolutely.....no way around it.......need a good earth ground! That means 1-3 8' copper stakes in the ground and tied securely to your pool ground lugs and equipment lugs.

I wouldn't let anyone GO NEAR the pool, let alone SWIM in it, when you feel ANY ELECTRICAL SHOCK WHATSOEVER!

Sorry about the "yelling" but this can be much more serious than you realize until someone dies as a result. Then the blame game begins.

Pool "code" is weak or non-existant in some states, so don't depend on your contractor to know proper building codes. I caught our electrical contractor trying to install 12 guage wire for 100ft of 100 amp 230VAC supply line to the equipment pad subpanel!

There's more misinformation on the internet than good information, unless you err on the side of caution and check your sources. Do a google search on fatal ground loops......if that doesn't scare you, nothing will.

Don't do electrical work "on the cheap". Especially on a salt water swimming pool!......lol

I'll shut up now.

STS